Forklifts of various kinds are well known in the art. Typically, forklifts include a maneuverable vehicle portion with a pair of forks mounted to a mast mechanism on the vehicle portion. The vehicle portion and the forks cooperate to pick up, maneuver, and set down loads. Traditional forklifts are rather large and heavy vehicles that are designed to be used in one area, such as a warehouse, and not to be transported from site to site. More recently, more maneuverable three wheel forklifts have been developed that are designed to be mounted and transported on a truck. Examples of such forklifts are shown in UK Patent Application GB 2,259,292A and U.S. Pat. No. 4,921,075 to Schumacher et al. This type of forklift has a pair of front wheels or tires and a single rear steering wheel. The forklift mechanism is generally positioned between the front wheels or tires. These types of forklifts are typically shorter, front to back, than traditional forklifts and their use of a single rear steering wheel makes them highly maneuverable. Also, they are designed to mount on the rear of a vehicle such as a truck or trailer for transport with the vehicle.
FIG. 1 provides an illustration of an exemplary three wheel forklift of the type discussed above. The forklift 2 includes a forklift frame 3 which is in turn supported by ground contacting wheels or tires 4. The front tires 4 are shown in FIG. 1. A third generally centrally mounted rear tire is also included, though not visible in FIG. 1. The forklift frame 3 supports an operator cab or operator location 5 where an operator normally resides to operate the various controls of the forklift 2. The forklift 2 includes a pair of forks 6 which are movable upwardly and downwardly relative to the frame 3. The forks 6 are supported by a mast 7 which in turn is connected to the frame 3. In addition to vertical movement of the forks, the forklift 2 also includes the ability to move the forks longitudinally fore and aft relative to the frame 3. This allows the forklift to “reach” forward to pick up or deposit a load. The longitudinal movement of the forks 6 relative to the frame 3 may be accomplished by longitudinal movement of the mast 7 relative to the frame 3 or by movement of the forks 6 or a fork support structure relative to a static mast. The forks 6 and/or mast 7 may also be tilted relative to the frame 3. In some models, the forks 6 may also be moved side to side relative to the frame and/or each other.
U.S. Pat. No. 5,575,604 to Dubosh et al. and U.S. Pat. No. 5,749,695 to Moffett et al. both show mounting systems for the newer type of three wheel forklift. In each case, a pair of fork tine receiving slots is provided in the rear of a vehicle and interconnects with the vehicle's frame. To mount the forklift to the rear of the frame, the forklift driver approaches the truck with the forks aligned with the receiving slots. The slots are a distance above the ground or surface on which the forklift and the vehicle are supported. The forklift operator inserts the forks into the slots until the body of the forklift is close to the back of the vehicle. At this point, the forks are inserted a significant distance into the slots. The operator then lowers the forks with respect to the body and/or frame of the forklift. Because the forks are inserted in the slots, this action lifts the forklift off the ground such that the forklift is supported by its forks in the slots. In this way, the forklift is “piggybacked” on the rear end of the vehicle with the mounting system.
Preferably, the mounting system also includes additional support for the forklift so that the entire force of supporting the forklift is not passed through the forks. For example, in the Moffett et al. patent, a pair of wheel rests is provided on the rear of the vehicle aligned with the front wheels on the forklift. After lifting the forklift off the ground by its forks, the operator hydraulically retracts the forks towards the forklift, thereby pulling the body of the forklift towards the rear of the vehicle. In this way, the user positions the front wheels on top of the wheel rests and then lowers the forklift body until the wheel rests are supporting a significant portion of the load of the forklift. Chains or other supports may also be provided for interconnecting the body of the forklift with the vehicle.
In the Dubosh et al. patent, a pair of hooks with upwardly directed openings are provided on the rear of the vehicle and corresponding fixed horizontal members are provided on the front of the forklift frame. The forklift is loaded onto the vehicle by inserting the forks into fork supports, lifting the forklift upwardly until the horizontal members are higher than the hooks, retracting the forks towards the forklift to move the horizontal members to a position directly above the hooks, and then lowering the forklift until the horizontal members engage the hooks and the forklift is supported. Wheel abutments are also provided on the vehicle and are engaged by the wheels of the forklift when the forklift is attached to the vehicle. The abutments are generally vertical members that engage the fronts of the wheels.
FIG. 2 illustrates a detailed view of a mounting system utilizing a hook 60 mounted to a frame 62 of a forklift that engages a horizontal member 64 that is attached to the rear of a vehicle 66. The forklift may be mounted to the vehicle using the same series of steps described above. However, as will be clear to those of skill in the art, the design discussed above and shown in FIG. 2 both require the forklift to be lifted upwardly and then moved forwardly in order to engage the hook and horizontal member with one another. This typically requires that an operator remain in the operator location as the forklift is lifted, moved forwardly and then engaged with the mounting system. The operator then must climb down from the elevated forklift to the ground. Removing the forklift from the vehicle requires an operator to perform the same operations in reverse. The operator must climb into the operator location in the elevated forklift and then operate the controls to lift the forklift so as to disengage the mounting system, move the forklift rearwardly to clear the hook and horizontal member from one another, and then lower the forklift until it is supported by the ground. Some or all of these operations may be time consuming, unsafe and/or uncomfortable for an operator since it requires climbing into a forklift that is supported above the ground.